1. Field of the Invention
The present invention relates to an improvement of measuring tape device, in particular, it refers to the hook piece that is designed to prevent the hook piece from slipping off from the object to be measured.
2. Description of Prior Art
With the increasing demand of surveying, the measuring tape devices get to be more widely used. A conventional measuring tape device 1, as shown in FIG. 1, comprises of a casing 11; a hollow space (not shown) is formed within the casing, which holds a bobbin (not shown); at the center of the casing 11 is the bobbin that is connected to the casing 11 with a coil spring (not shown). A measuring tape 12 having scales is contained inside the casing 11, one end of the measuring tape 12 is connected to the spring and it is wound around the bobbin, and the other end of the tape 12 extends outside of the casing 11 through an aperture. A hook piece 13 is attached at the end of the measuring tape.
During the process of taking measurement, the hook plate 14 of the hook piece 13 is attached to an object and then the measuring tape 12 is pulled away from outside of the casing 11, then the extended tape 12 is locked in place using the device's locking mechanism 16, and the measure can be read from the scales printed on the tape 12, as such, the length of the object to be measured or distance from the object is obtained.
Because the hook piece 13 of said conventional measuring tape device can measure the length or distance of an object by hooking, when the object has a large volume or the distance is longer than usual, it is difficult for the hook piece 13 to fix onto the object and then the measuring accuracy can not be obtained.
In order to improve said problem happened in conventional measuring tape device, U.S. Pat. No. 6,546,644B2 discloses a measuring tape device having a measuring tape with concaved upper surface, such that the measuring tape can be horizontally supported when it is extended outward from the casing, and a magnet is attached to the end of the hook piece, so as to fix the end of measuring tape onto an object to be measured.
US Patent Publication No. 2004/0064962A1 discloses a soft hook piece for measuring tape device having a soft housing enveloping the hook piece, in measuring an object, by the function of soft housing, the hook piece can firmly hook onto the object to be measured. In addition, a magnetic element is also adhered onto the surface of said hook piece.
Although the above disclosed improved arts had improved the disadvantages of conventional measuring tape device, however, since the magnetic element is adhered directly onto the surface of hook piece, it causes the magnetic element to be easily come apart from the surface of hook piece after the measuring tape is used extensively. In addition, because the hook piece is fixed onto the measuring tape and can not be moved, the accuracy of measuring shall be reduced due to the thickness or installment of magnetic element.